/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * KVM/MIPS: MIPS specific KVM APIs
 *
 * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
 * Authors: Sanjay Lal <sanjayl@kymasys.com>
*/

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/bootmem.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>

#include <linux/kvm_host.h>

#include "kvm_mips_int.h"
#include "kvm_mips_comm.h"

#define CREATE_TRACE_POINTS
#include "trace.h"

#ifndef VECTORSPACING
#define VECTORSPACING 0x100	/* for EI/VI mode */
#endif

#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
struct kvm_stats_debugfs_item debugfs_entries[] = {
	{ "wait", VCPU_STAT(wait_exits) },
	{ "cache", VCPU_STAT(cache_exits) },
	{ "signal", VCPU_STAT(signal_exits) },
	{ "interrupt", VCPU_STAT(int_exits) },
	{ "cop_unsuable", VCPU_STAT(cop_unusable_exits) },
	{ "tlbmod", VCPU_STAT(tlbmod_exits) },
	{ "tlbmiss_ld", VCPU_STAT(tlbmiss_ld_exits) },
	{ "tlbmiss_st", VCPU_STAT(tlbmiss_st_exits) },
	{ "addrerr_st", VCPU_STAT(addrerr_st_exits) },
	{ "addrerr_ld", VCPU_STAT(addrerr_ld_exits) },
	{ "syscall", VCPU_STAT(syscall_exits) },
	{ "resvd_inst", VCPU_STAT(resvd_inst_exits) },
	{ "break_inst", VCPU_STAT(break_inst_exits) },
	{ "flush_dcache", VCPU_STAT(flush_dcache_exits) },
	{ "halt_wakeup", VCPU_STAT(halt_wakeup) },
	{NULL}
};

static int kvm_mips_reset_vcpu(struct kvm_vcpu *vcpu)
{
	int i;
	for_each_possible_cpu(i) {
		vcpu->arch.guest_kernel_asid[i] = 0;
		vcpu->arch.guest_user_asid[i] = 0;
	}
	return 0;
}

gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
	return gfn;
}

/* XXXKYMA: We are simulatoring a processor that has the WII bit set in Config7, so we
 * are "runnable" if interrupts are pending
 */
int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
	return !!(vcpu->arch.pending_exceptions);
}

int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
	return 1;
}

int kvm_arch_hardware_enable(void *garbage)
{
	return 0;
}

void kvm_arch_hardware_disable(void *garbage)
{
}

int kvm_arch_hardware_setup(void)
{
	return 0;
}

void kvm_arch_hardware_unsetup(void)
{
}

void kvm_arch_check_processor_compat(void *rtn)
{
	int *r = (int *)rtn;
	*r = 0;
	return;
}

static void kvm_mips_init_tlbs(struct kvm *kvm)
{
	unsigned long wired;

	/* Add a wired entry to the TLB, it is used to map the commpage to the Guest kernel */
	wired = read_c0_wired();
	write_c0_wired(wired + 1);
	mtc0_tlbw_hazard();
	kvm->arch.commpage_tlb = wired;

	kvm_debug("[%d] commpage TLB: %d\n", smp_processor_id(),
		  kvm->arch.commpage_tlb);
}

static void kvm_mips_init_vm_percpu(void *arg)
{
	struct kvm *kvm = (struct kvm *)arg;

	kvm_mips_init_tlbs(kvm);
	kvm_mips_callbacks->vm_init(kvm);

}

int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
	if (atomic_inc_return(&kvm_mips_instance) == 1) {
		kvm_info("%s: 1st KVM instance, setup host TLB parameters\n",
			 __func__);
		on_each_cpu(kvm_mips_init_vm_percpu, kvm, 1);
	}


	return 0;
}

void kvm_mips_free_vcpus(struct kvm *kvm)
{
	unsigned int i;
	struct kvm_vcpu *vcpu;

	/* Put the pages we reserved for the guest pmap */
	for (i = 0; i < kvm->arch.guest_pmap_npages; i++) {
		if (kvm->arch.guest_pmap[i] != KVM_INVALID_PAGE)
			kvm_mips_release_pfn_clean(kvm->arch.guest_pmap[i]);
	}

	if (kvm->arch.guest_pmap)
		kfree(kvm->arch.guest_pmap);

	kvm_for_each_vcpu(i, vcpu, kvm) {
		kvm_arch_vcpu_free(vcpu);
	}

	mutex_lock(&kvm->lock);

	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
		kvm->vcpus[i] = NULL;

	atomic_set(&kvm->online_vcpus, 0);

	mutex_unlock(&kvm->lock);
}

void kvm_arch_sync_events(struct kvm *kvm)
{
}

static void kvm_mips_uninit_tlbs(void *arg)
{
	/* Restore wired count */
	write_c0_wired(0);
	mtc0_tlbw_hazard();
	/* Clear out all the TLBs */
	kvm_local_flush_tlb_all();
}

void kvm_arch_destroy_vm(struct kvm *kvm)
{
	kvm_mips_free_vcpus(kvm);

	/* If this is the last instance, restore w